The Department of Biomedicine

BBB seminar: Carlos Gómez-Moreno Calera

Molecular monolayers of a redox enzyme for the construction of biosensors

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Carlos Gómez-Moreno Calera
Department of Biochemistry and Molecular and Cell Biology, University of Zaragoza, Spain

Engineered proteins offer interesting systems not only for studies of protein structure/function properties but also for the design of devices detecting the presence of compounds that can be of interest from clinical and environmental points of view. Redox proteins, which include both metallo and flavoproteins, present a drawback when they are used in electrochemical devices, since their redox cofactor is isolated from the electrode used to detect the presence of the analyte. For this reason it is necessary to use mediators, compounds that help to communicate between the enzyme and the electrode. In this lecture I present an original strategy that has been used to connect electrically the enzyme ferredoxin-NADP+ reductase (FNR) with a gold electrode by chemically crosslinking the enzyme to a group of small carrier molecules. Moreover, I present a strategy we have used to tune the orientation of the immobilized FNR protein on electrodes by using site-directed mutagenesis. Depending on the orientation of the immobilized enzyme, the rate of electron transfer and NADPH oxidation is found to vary. These results indicate that protein engineering can be used both to get a deeper knowledge of the mechanism of enzyme function and to develop analytical devices that could be of great interest for the detection of important molecules.

Host: Aurora Martínez, Department for Biomedicine

Carlos Gómez-Moreno Calera, Professor at the Department of Biochemistry and Molecular and Cell Biology, University of Zaragoza, Spain, leads an active and productive group with research focus on structure and function of redox proteins. His methodological profile covers biophysics, notably stop-flow kinetics, and molecular modelling. Since 2002 his group has an Erasmus partnership with the group of Aurora Martinez at the Department of Biomedicine.

Main projects:

· The photosynthetic electron transfer from photosystem I to ferredoxin-NADP+ reductase.
· Design of enzymatic systems that allow efficient coupling of redox proteins from the photosynthetic electron transfer chain with those from the chain that leads to the synthesis of steroids hormones in mammals.
· The action mechanisms in redox flavoproteins. Versatility, adaptation and biotechnological redesign of flavin properties within the protein environment.
· Structural and functional relationships in different electron transfer chains involving flavoproteins.